package com.mask.token.service;

import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.stereotype.Service;

import java.time.Instant;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicLong;

/**
 * Token安全审计服务
 * 提供安全事件记录、异常检测、风险评估等功能
 *
 * @author mask
 * @since 1.0.0
 */
@Slf4j
@Service
@RequiredArgsConstructor
@ConditionalOnProperty(name = "mask.token.audit.enabled", havingValue = "true", matchIfMissing = false)
public class MaskTokenAuditService {

    // 安全事件记录
    private final ConcurrentHashMap<String, SecurityEvent> securityEvents = new ConcurrentHashMap<>();
    
    // 异常检测统计
    private final AtomicLong suspiciousLoginAttempts = new AtomicLong(0);
    private final AtomicLong tokenAbuseAttempts = new AtomicLong(0);
    private final AtomicLong securityViolations = new AtomicLong(0);

    /**
     * 记录安全事件
     */
    public void recordSecurityEvent(String eventType, String userId, String details, SecurityLevel level) {
        try {
            SecurityEvent event = new SecurityEvent();
            event.setEventType(eventType);
            event.setUserId(userId);
            event.setDetails(details);
            event.setLevel(level);
            event.setTimestamp(Instant.now());
            event.setIpAddress(getCurrentIpAddress());
            event.setUserAgent(getCurrentUserAgent());
            
            String eventId = generateEventId();
            securityEvents.put(eventId, event);
            
            // 根据安全级别处理
            handleSecurityEvent(event);
            
            log.info("安全事件已记录: {} - {} - {}", eventType, userId, level);
        } catch (Exception e) {
            log.error("记录安全事件失败", e);
        }
    }

    /**
     * 检测异常登录
     */
    public boolean detectAbnormalLogin(String userId, String ipAddress, String userAgent) {
        try {
            // 检查登录频率
            if (isHighFrequencyLogin(userId)) {
                recordSecurityEvent("HIGH_FREQUENCY_LOGIN", userId, 
                    "用户登录频率过高", SecurityLevel.HIGH);
                return true;
            }
            
            // 检查IP异常
            if (isAbnormalIp(userId, ipAddress)) {
                recordSecurityEvent("ABNORMAL_IP_LOGIN", userId, 
                    "异常IP地址登录: " + ipAddress, SecurityLevel.HIGH);
                return true;
            }
            
            // 检查设备异常
            if (isAbnormalDevice(userId, userAgent)) {
                recordSecurityEvent("ABNORMAL_DEVICE_LOGIN", userId, 
                    "异常设备登录: " + userAgent, SecurityLevel.MEDIUM);
                return true;
            }
            
            return false;
        } catch (Exception e) {
            log.error("检测异常登录失败", e);
            return false;
        }
    }

    /**
     * 检测Token滥用
     */
    public boolean detectTokenAbuse(String token, String userId) {
        try {
            // 检查Token使用频率
            if (isHighFrequencyTokenUsage(token)) {
                recordSecurityEvent("TOKEN_ABUSE", userId, 
                    "Token使用频率过高: " + token, SecurityLevel.HIGH);
                tokenAbuseAttempts.incrementAndGet();
                return true;
            }
            
            // 检查Token异常访问
            if (isAbnormalTokenAccess(token, userId)) {
                recordSecurityEvent("ABNORMAL_TOKEN_ACCESS", userId, 
                    "Token异常访问: " + token, SecurityLevel.MEDIUM);
                return true;
            }
            
            return false;
        } catch (Exception e) {
            log.error("检测Token滥用失败", e);
            return false;
        }
    }

    /**
     * 风险评估
     */
    public RiskAssessment assessRisk(String userId, String ipAddress, String userAgent) {
        RiskAssessment assessment = new RiskAssessment();
        assessment.setUserId(userId);
        assessment.setTimestamp(Instant.now());
        assessment.setRiskLevel(RiskLevel.LOW);
        assessment.setRiskScore(0);
        
        try {
            int riskScore = 0;
            
            // 检查登录频率风险
            if (isHighFrequencyLogin(userId)) {
                riskScore += 30;
            }
            
            // 检查IP风险
            if (isAbnormalIp(userId, ipAddress)) {
                riskScore += 40;
            }
            
            // 检查设备风险
            if (isAbnormalDevice(userId, userAgent)) {
                riskScore += 20;
            }
            
            // 检查时间风险（非工作时间登录）
            if (isOffHoursLogin()) {
                riskScore += 10;
            }
            
            assessment.setRiskScore(riskScore);
            
            // 确定风险级别
            if (riskScore >= 70) {
                assessment.setRiskLevel(RiskLevel.HIGH);
            } else if (riskScore >= 40) {
                assessment.setRiskLevel(RiskLevel.MEDIUM);
            } else {
                assessment.setRiskLevel(RiskLevel.LOW);
            }
            
            // 记录风险评估
            recordSecurityEvent("RISK_ASSESSMENT", userId, 
                "风险评估完成: " + assessment.getRiskLevel() + " (分数: " + riskScore + ")", 
                mapRiskLevelToSecurityLevel(assessment.getRiskLevel()));
            
        } catch (Exception e) {
            log.error("风险评估失败", e);
            assessment.setRiskLevel(RiskLevel.HIGH);
            assessment.setRiskScore(100);
        }
        
        return assessment;
    }

    /**
     * 获取安全统计
     */
    public SecurityStatistics getSecurityStatistics() {
        SecurityStatistics stats = new SecurityStatistics();
        stats.setTotalSecurityEvents(securityEvents.size());
        stats.setSuspiciousLoginAttempts(suspiciousLoginAttempts.get());
        stats.setTokenAbuseAttempts(tokenAbuseAttempts.get());
        stats.setSecurityViolations(securityViolations.get());
        stats.setTimestamp(Instant.now());
        
        return stats;
    }

    /**
     * 清理过期安全事件
     */
    public void cleanExpiredSecurityEvents() {
        try {
            Instant cutoffTime = Instant.now().minusSeconds(86400); // 24小时前
            
            securityEvents.entrySet().removeIf(entry -> {
                SecurityEvent event = entry.getValue();
                return event.getTimestamp().isBefore(cutoffTime);
            });
            
            log.info("清理过期安全事件完成，剩余事件数: {}", securityEvents.size());
        } catch (Exception e) {
            log.error("清理过期安全事件失败", e);
        }
    }

    // 私有方法实现
    private boolean isHighFrequencyLogin(String userId) {
        // 实现高频登录检测逻辑
        return false;
    }

    private boolean isAbnormalIp(String userId, String ipAddress) {
        // 实现异常IP检测逻辑
        return false;
    }

    private boolean isAbnormalDevice(String userId, String userAgent) {
        // 实现异常设备检测逻辑
        return false;
    }

    private boolean isHighFrequencyTokenUsage(String token) {
        // 实现Token高频使用检测逻辑
        return false;
    }

    private boolean isAbnormalTokenAccess(String token, String userId) {
        // 实现Token异常访问检测逻辑
        return false;
    }

    private boolean isOffHoursLogin() {
        // 实现非工作时间登录检测逻辑
        return false;
    }

    private void handleSecurityEvent(SecurityEvent event) {
        switch (event.getLevel()) {
            case HIGH:
                // 高风险事件处理
                securityViolations.incrementAndGet();
                log.warn("高风险安全事件: {} - {}", event.getEventType(), event.getDetails());
                break;
            case MEDIUM:
                // 中风险事件处理
                log.info("中风险安全事件: {} - {}", event.getEventType(), event.getDetails());
                break;
            case LOW:
                // 低风险事件处理
                log.debug("低风险安全事件: {} - {}", event.getEventType(), event.getDetails());
                break;
        }
    }

    private String generateEventId() {
        return "SEC_" + System.currentTimeMillis() + "_" + (int)(Math.random() * 1000);
    }

    private String getCurrentIpAddress() {
        // 实现获取当前IP地址的逻辑
        return "127.0.0.1";
    }

    private String getCurrentUserAgent() {
        // 实现获取当前User Agent的逻辑
        return "Unknown";
    }

    private SecurityLevel mapRiskLevelToSecurityLevel(RiskLevel riskLevel) {
        switch (riskLevel) {
            case HIGH: return SecurityLevel.HIGH;
            case MEDIUM: return SecurityLevel.MEDIUM;
            case LOW: return SecurityLevel.LOW;
            default: return SecurityLevel.LOW;
        }
    }

    // 内部类定义
    public static class SecurityEvent {
        private String eventType;
        private String userId;
        private String details;
        private SecurityLevel level;
        private Instant timestamp;
        private String ipAddress;
        private String userAgent;

        // Getters and Setters
        public String getEventType() { return eventType; }
        public void setEventType(String eventType) { this.eventType = eventType; }
        public String getUserId() { return userId; }
        public void setUserId(String userId) { this.userId = userId; }
        public String getDetails() { return details; }
        public void setDetails(String details) { this.details = details; }
        public SecurityLevel getLevel() { return level; }
        public void setLevel(SecurityLevel level) { this.level = level; }
        public Instant getTimestamp() { return timestamp; }
        public void setTimestamp(Instant timestamp) { this.timestamp = timestamp; }
        public String getIpAddress() { return ipAddress; }
        public void setIpAddress(String ipAddress) { this.ipAddress = ipAddress; }
        public String getUserAgent() { return userAgent; }
        public void setUserAgent(String userAgent) { this.userAgent = userAgent; }
    }

    public static class RiskAssessment {
        private String userId;
        private Instant timestamp;
        private RiskLevel riskLevel;
        private int riskScore;

        // Getters and Setters
        public String getUserId() { return userId; }
        public void setUserId(String userId) { this.userId = userId; }
        public Instant getTimestamp() { return timestamp; }
        public void setTimestamp(Instant timestamp) { this.timestamp = timestamp; }
        public RiskLevel getRiskLevel() { return riskLevel; }
        public void setRiskLevel(RiskLevel riskLevel) { this.riskLevel = riskLevel; }
        public int getRiskScore() { return riskScore; }
        public void setRiskScore(int riskScore) { this.riskScore = riskScore; }
    }

    public static class SecurityStatistics {
        private int totalSecurityEvents;
        private long suspiciousLoginAttempts;
        private long tokenAbuseAttempts;
        private long securityViolations;
        private Instant timestamp;

        // Getters and Setters
        public int getTotalSecurityEvents() { return totalSecurityEvents; }
        public void setTotalSecurityEvents(int totalSecurityEvents) { this.totalSecurityEvents = totalSecurityEvents; }
        public long getSuspiciousLoginAttempts() { return suspiciousLoginAttempts; }
        public void setSuspiciousLoginAttempts(long suspiciousLoginAttempts) { this.suspiciousLoginAttempts = suspiciousLoginAttempts; }
        public long getTokenAbuseAttempts() { return tokenAbuseAttempts; }
        public void setTokenAbuseAttempts(long tokenAbuseAttempts) { this.tokenAbuseAttempts = tokenAbuseAttempts; }
        public long getSecurityViolations() { return securityViolations; }
        public void setSecurityViolations(long securityViolations) { this.securityViolations = securityViolations; }
        public Instant getTimestamp() { return timestamp; }
        public void setTimestamp(Instant timestamp) { this.timestamp = timestamp; }
    }

    public enum SecurityLevel {
        LOW, MEDIUM, HIGH
    }

    public enum RiskLevel {
        LOW, MEDIUM, HIGH
    }
}
